1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method.
2. Description of the Related Art
Conventionally, some image forming apparatuses using an electrophotographic process, such as laser printers and digital copying machines, have used multiple beams in optical scanning to speed up image formation and to increase image density.
Upon performing duplex printing, such an image forming apparatus records an image on the first side of a sheet, fixes the image thereon, and records another image on the second side. A scaling difference of 0.2 percent to 0.4 percent occurs between the image printed on the first side and the image printed on the second side. Such a scaling difference is caused by lost moisture in the sheet, and the scaling difference varies depending on the type of the sheet.
Therefore, to adjust scaling and to correct a distortion, correction processes such as thinning out or insertion of pixels are performed, for example. Japanese Patent Application Laid-open No. 2009-83472, for example, discloses an invention of an image forming apparatus and the like that perform enlarging correction on an image by periodically adding pixels along a vertical direction and a horizontal direction of image data.
In addition, Japanese Patent No. 4253843 discloses an invention of an image forming apparatus that performs an image scanning process where regularly arranged pixels are added or deleted. In the invention according to Japanese Patent No. 4253843, deterioration of image quality during the process of enlarging or reducing the image is prevented by utilizing the information about the positions of pixels to be added or deleted during the screen process.
However, the invention of the image forming apparatus and the like disclosed in Japanese Patent Application Laid-open No. 2009-83472 has not considered about changing the positions of the pixels to be added or deleted based on the characteristics of an image. Furthermore, in the invention of the image forming apparatus and the like disclosed in Japanese Patent No. 4253843, the screen process is performed every time the positions of the pixels to be added or deleted are changed, and, therefore, the screen process must be performed every time there is a scaling difference.
The present invention is made in consideration of the above, and to solve these problems. An object of the present invention is to provide an image processing apparatus and an image processing method that can easily reduce image degradation during the process of enlarging and reducing an image.